XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 3431
above 100%, which is clearly not right. Few of the ions
are approximately mass balanced. This can be attributed, at
least partly, in higher errors associated with measuring very
small amounts compared to measuring medium or large
amounts. For the same reason it is understandable that the
figure for manganese is reasonable being the main con-
stituent either in the solid or liquid stream. Its apparently
elevated amount is owing to the added KMnO4 as oxidant.
The same applies to potassium. These results, therefore,
should be treated only as very rough indications particu-
larly in relation to impurity ions and those that are suscep-
tible to interference in spectroscopic analytical techniques.
Notwithstanding these uncertainties, these results pro-
vided insights that are useful in refining the technique as a
step in the production of high purity manganese products
including at 4N level. To mention two points, one is the
use of an oxidant that does not contain potassium or any
metal ion and the other is dilution of the feed prior to pre-
cipitation. Regarding the former, excluding potassium, for
example, as an impurity would increase the purity of the
MnO2 product to 99.93%. Dilution of the feed prior to
precipitation of manganese, which is stoichiometric, would
almost certainly inhibit the co-precipitation of most of the
impurity ions, and probably most are only entrained in the
crystal lattice of the major precipitating constituent ions,
such as manganese dioxide in this case. It is thus reasonable
to suggest that the technique can be refined to achieve a
much higher purity of MnO2 precipitate bringing it closer
to the target 4N purity.
RELEACHING MANGANESE DIOXIDE
This was carried out in a similar way to the leaching of man-
ganese from the ore. The results show that complete disso-
lution of the MnO2 precipitate was achieved with ease. The
assay of the resulting PLS is summarised in Table 6. This
means the approach is straightforward and ready for incor-
poration in a suitable application.
COPPER REMOVAL USING IX
Copper is known to preferentially extracts over other tran-
sition metals with most extractants. Hence, if it is an impu-
rity in a feed to a solvent extraction circuit, such as the
envisaged SX of manganese in the present work, its removal
prior to SX is necessary. This section describes the removal
of the copper by ion exchange (IX) from the PLS of the re-
leached MnO2. The resin, Purolite MTS9600, as well as the
test procedure used in this test were supplied by Purolite ®.
InterChem in Melbourne facilitated the contact. The results
are summarised in Table 7. The t =0 sample refers to the
PLS stream prior to copper removal and t =2 sample refers
to the PLS stream after Cu removal.
The result show that over 85% of the copper was
removed despite its very small amount (9.6 mg/L) in the
feed. Some manganese was also removed as well as some
other metal ions were removed also but they can all be
eluted from the resin and reprocessed.
Table 4. Constituents (%)of the MnO2 precipitate
Element %
Al 0.01
Ba 0.01
Ca 0.01
Co 0.004
Cr 0.01
Cu 0.01
Fe 0.01
K 1.08
Mg 0.04
Mn 55.9
Na 0.028
Ni 0.01
P 0.01
SO3 0.65
S 0.26
Si 0.24
Ti 0.01
V 0.01
Zn 0.01
Purity 98.56
Table 5. Accountability for each element in Mn precipitation
experiment
Element Accountability (%)
Al 300
Ba 601
Ca 97
Co 108
Cr 601
Cu 4893
Fe 300
K 1451
Mg 115
Mn 161
Na 106
Ni 101
P 601
S 101
Si 601
Ti 601
V 101
Zn 601
above 100%, which is clearly not right. Few of the ions
are approximately mass balanced. This can be attributed, at
least partly, in higher errors associated with measuring very
small amounts compared to measuring medium or large
amounts. For the same reason it is understandable that the
figure for manganese is reasonable being the main con-
stituent either in the solid or liquid stream. Its apparently
elevated amount is owing to the added KMnO4 as oxidant.
The same applies to potassium. These results, therefore,
should be treated only as very rough indications particu-
larly in relation to impurity ions and those that are suscep-
tible to interference in spectroscopic analytical techniques.
Notwithstanding these uncertainties, these results pro-
vided insights that are useful in refining the technique as a
step in the production of high purity manganese products
including at 4N level. To mention two points, one is the
use of an oxidant that does not contain potassium or any
metal ion and the other is dilution of the feed prior to pre-
cipitation. Regarding the former, excluding potassium, for
example, as an impurity would increase the purity of the
MnO2 product to 99.93%. Dilution of the feed prior to
precipitation of manganese, which is stoichiometric, would
almost certainly inhibit the co-precipitation of most of the
impurity ions, and probably most are only entrained in the
crystal lattice of the major precipitating constituent ions,
such as manganese dioxide in this case. It is thus reasonable
to suggest that the technique can be refined to achieve a
much higher purity of MnO2 precipitate bringing it closer
to the target 4N purity.
RELEACHING MANGANESE DIOXIDE
This was carried out in a similar way to the leaching of man-
ganese from the ore. The results show that complete disso-
lution of the MnO2 precipitate was achieved with ease. The
assay of the resulting PLS is summarised in Table 6. This
means the approach is straightforward and ready for incor-
poration in a suitable application.
COPPER REMOVAL USING IX
Copper is known to preferentially extracts over other tran-
sition metals with most extractants. Hence, if it is an impu-
rity in a feed to a solvent extraction circuit, such as the
envisaged SX of manganese in the present work, its removal
prior to SX is necessary. This section describes the removal
of the copper by ion exchange (IX) from the PLS of the re-
leached MnO2. The resin, Purolite MTS9600, as well as the
test procedure used in this test were supplied by Purolite ®.
InterChem in Melbourne facilitated the contact. The results
are summarised in Table 7. The t =0 sample refers to the
PLS stream prior to copper removal and t =2 sample refers
to the PLS stream after Cu removal.
The result show that over 85% of the copper was
removed despite its very small amount (9.6 mg/L) in the
feed. Some manganese was also removed as well as some
other metal ions were removed also but they can all be
eluted from the resin and reprocessed.
Table 4. Constituents (%)of the MnO2 precipitate
Element %
Al 0.01
Ba 0.01
Ca 0.01
Co 0.004
Cr 0.01
Cu 0.01
Fe 0.01
K 1.08
Mg 0.04
Mn 55.9
Na 0.028
Ni 0.01
P 0.01
SO3 0.65
S 0.26
Si 0.24
Ti 0.01
V 0.01
Zn 0.01
Purity 98.56
Table 5. Accountability for each element in Mn precipitation
experiment
Element Accountability (%)
Al 300
Ba 601
Ca 97
Co 108
Cr 601
Cu 4893
Fe 300
K 1451
Mg 115
Mn 161
Na 106
Ni 101
P 601
S 101
Si 601
Ti 601
V 101
Zn 601